1. Field of the Invention
The disclosure relates to a low dropout (LDO) regulator, and more particularly to a LDO regulator with high stability.
2. Description of the Related Art
Voltage regulators are commonly used in the power management systems of computers, mobile phones, automobiles and many other electronic products. Generally, voltage regulators are configured to convert unstable power supply voltage into stable power supply voltage. A low dropout (LDO) regulator has a low input-to-output voltage difference between an input terminal where an unstable power supply voltage is inputted and an output terminal where a stable power supply voltage is outputted. “Dropout voltage” refers to the input-to-output voltage difference, whereby the regulator ceases to regulate against further reductions in the input voltage. Ideally, the dropout voltage should be as low as possible, to reduce the power consumption while still maintaining regulation performance.
In the conventional LDO regulator design, a low frequency pole, at about 200 KHz to 500 KHz, is usually generated at the feedback terminal Because the low frequency pole falls within the operation frequency band of the LDO regulator, the stability of the LDO regulator is seriously downgraded. However, stability is an important factor of the LDO regulator.
Therefore, a novel LDO regulator, which can push the pole to a high frequency band while still maintaining high stability, is highly required.